ƚ PR  .  &` & MathType-n  $  ^Times New Romanww 0wfm-2  212 n 132  212 n 612 212 n712 712 n 212 312 n11Symbols tww 0wfm-2 ` =12 `o +12 `M=12 `+12 ``=1Times New Romanww 0wfm-2 `Lx1 & "Systemmfm !-